Aluminum electrolyte lithium extraction single-effect evaporator system

The electrolytic aluminum production process generates a large amount of lithium-containing aluminum electrolyte waste residue. This residue contains valuable lithium resources, and traditional treatment methods not only waste resources but also pose environmental pollution risks. Our single-effect evaporator system for lithium extraction from aluminum electrolyte is specifically designed to extract lithium resources from aluminum electrolyte, maximizing the resource utilization of waste residue and economic benefits.

I. Background and Technical Route of the Lithium Extraction System from Aluminum Electrolyte

Lithium extraction from aluminum electrolyte is one of the important technological directions for current lithium resource recovery. After processes such as grinding, thermal dissolution, and filtration, the impurity electrolyte contains various salts such as LiCl, KCl, and NaCl in the filtrate. By adding Na₂CO₃, LiCl precipitates and separates as Li₂CO₃, and the remaining filtrate enters the evaporation and crystallization system.

Our single-effect evaporator system is a key link in this process chain, responsible for evaporating and concentrating the sodium and potassium-containing filtrate to recover sodium chloride and potassium chloride products, while simultaneously achieving the recycling of process water.

II. Composition and Working Process of Single-Effect Evaporator System for Lithium Extraction from Aluminum Electrolyte

1. Evaporation and Concentration Unit: Utilizing MVR or single-effect evaporation technology, the salt-containing filtrate is evaporated and concentrated. The principle of MVR evaporator technology is to use secondary steam generated by the evaporator, which, after being compressed by a steam compressor, is reduced from low-grade steam to high-grade steam at a higher saturation temperature, and then returned to the heating source for the evaporator. For smaller processing volumes, single-effect evaporators offer advantages such as low investment and ease of operation.

2. Crystallization and Separation Unit: The solubility of sodium chloride is minimally affected by temperature changes. Steam heating causes the solvent (water) to evaporate and vaporize, continuously concentrating the liquid and increasing the sodium chloride concentration until supersaturation is reached, leading to crystallization. The system is equipped with a high-efficiency crystallizer and centrifugal separation equipment to achieve efficient salt separation.

3. Mother Liquor Recovery System: The separated mother liquor is returned to the evaporation system for further processing, achieving a closed-loop material circulation and maximizing resource recovery.

III. Technical Advantages of Single-Effect Evaporator System for Lithium Extraction from Aluminum Electrolyte

1. High Efficiency and Energy Saving: The energy consumption of the system using MVR technology is only about 50% of that of traditional evaporators. Even single-effect evaporators achieve high energy efficiency through optimized heat exchange networks and condensate waste heat recovery.

2. Comprehensive Resource Utilization: The system not only recovers lithium resources but also byproducts such as sodium chloride and potassium chloride, achieving full-component utilization of aluminum electrolyte waste. According to actual production data, the removal rate of Li in the aluminum electrolyte reaches 55-70%, and the removal rate of K reaches 40-50%.

3. Process Water Reuse: The high-quality condensate produced by evaporation can be directly reused in the hot dissolution process, achieving a closed-loop circulation of process water and reducing fresh water consumption.

4. High Degree of Automation: The system is equipped with an advanced automatic control system, achieving precise control of the evaporation process. Operators only need to monitor key parameters, greatly reducing labor intensity and operational difficulty.

5. Economic and Environmental Benefits: Taking a comprehensive aluminum electrolyte resource utilization project as an example, it processes approximately 88,000 tons of impurity electrolytes annually, recovering 4,477 tons of lithium carbonate and 560 tons of potassium chloride, while simultaneously producing cryolite, which is reused as a raw material for electrolytic aluminum. The project boasts a short total investment payback period and substantial annual profits, while simultaneously addressing the environmental issues associated with waste residue storage, achieving a win-win situation for both economic and environmental benefits.

6. System Configuration Options

Based on the customer's processing scale and site conditions, we offer:

MVR Evaporation System: Suitable for scenarios with large processing volumes and high steam costs, offering significant energy savings.

Single-Effect Evaporation System: Suitable for scenarios with smaller processing volumes and limited investment budgets, offering high cost-effectiveness.

Combined Process: MVR pre-concentration + single-effect crystallization, balancing energy saving and investment cost.